US2673953A - Variable regulated ignitron rectifier - Google Patents

Description

March 30, 1954 H. H. WITTENBERG 2,673,953

VARIABLE REGULATED IGNITRON RECTIFIER Filed June 14. 1951 INVENTOR WA! w/zmwis ATTORNEY Patented Mar. 30, 1954 VARIABLE REGULATED IGNITRON RECTIFIER Hubert H. Wittenberg, Radio Corporation of Delaware Lancaster, Pa., assignor to of America, a corporation Application June 14, 1951, Serial No. 231,563

3 Claims- (Cl. 32118) My invention relates to electrical control circuits and in particular to circuits'for controlling the output voltage of a half-wave rectifier.

. It is an objectof my invention to provide a control circuit in which output voltages can be obtained at very high currents.

A further object of my invention is to provide a simple and inexpensive means for regulating output voltage of a half-wave the direct current rectifier.

Still another object of my invention is to provide a control circuit in which automatic means are provided to compensate for output voltage variations.

In general, my invention comprises a multiphase half-wave rectifier in which several ig-.

nitrons form the rectifying portion of the circuit. In the example to provide a six phase half-wave rectifier in which gaseous discharge tubes of the thyratron type serve to fire the ignitrons. current voltage from a phase shifting network, in parallel to the direct current output voltage of thecircuit, controls the firing a way that the voltage applied to a load resistance is set at a predetermined value.

The above objects are accomplished by the structure and arrangement set forth in the following description when taken in connection with the accompanying drawing, in which the single figure illustrates in diagrammatic form a circuit:

to which such objects are particularly adapted.

Referring to the drawing, a three phase supply;- 45 supplies the delta conof alternating current nected primaries 46, 41, which primaries are connected in parallel. The rectifier portion of the circuit includes, in the illustration shown, six ignitrons indicated by the numerals 31 through 42. The transformer secondaries which are indicated by the letters A through L, provide plate and grid excitation for the ignitron rectifiers. The connections between thetransformer. sec ondaries and the ignitrons correspond to the letters as shown on the drawing, the actual connections having been omitted for purposes of clarity.

Current for the alternating current windings 22 and 22' of a saturable reactor, which are in the network contained within the dotted lines 23, is obtained from the three current input source 45. Also in the network 23 the primary winding 28 of a transformer 21, is connected as a bridge between the center tappf resistor 2! and the junction of the alternating current windings 22 and 22', and

illustrated, I employ six ignitrons An alternating tubes in such.

phase alternating I a fixed resistor- 2| The secondary windings of the transrorniel 21 are indicated by the numerals 29 and 30, such transformer being used to feed the identical firing tubes 3| and 32, containing a plate, a cathode, and a control grid, in push-pull fashion through resistors 35 and 36. In the example illustrated, electronic tubes 3| and 32 are of the thyratron type. Two other similar networks, 24 and 25, feed four additional electronic tubes identical to tubes 3| and 32, previously described. These tubes have also been omitted for purposes of clarity. In this connection, it should be stated that the box diagrams designated by the numerals 24 and 25 are schematic representations of net-- I works identical to the network 23-.

for the control phase is contained within the dotted lines [0 is supplied through the full-wave rectifier 50, which in the example illustrated is of the gaseous discharge type. The single phase alternating current supply for such rectifier is supplied by the secondary winding 49 of a transformer. The primary winding of the transformer designated by the numeral 48 is supplied with current by the input source of the three phase alternating current 45.

' The direct current output voltage of the cir cuit is obtained across the load resistor H, such" load resistor being connected in parallel to the cathode resistor 9 of space discharge device l2; The object of this connection will. become apparent when the. operation of the phase shifting network is described. The. network. I 0 is used to control the timing ofthe firing tubes.3l and 32, and the four addi-. tional firing tubes not shown in the drawing. In the circuit arrangement illustrated, the direct: current output voltage across the load resistor; I I is set by adjustments made in the voltage po tentiometer 5, thereby providing a simple and effective means for controlling and regulating the; rectified output voltage-from the ignitrons.

As previously described, the cathode resistor 9 v of space discharge device 12 is connected in parallel to a load resistor H. An electronic tube l2 containing at least a plate, a control electrode. and a cathode, is included within the phase shifting network. In the illustration shown, the electronic tube I2 is of the pentode type. The control grid l3 of this tube is connected in series through a resistance M to the variable voltage potentiometer I5, so that the current of the plate #6 of such tube can be controlled by varying the resistance of the potentiometer. This, in turn. controls the flow of current in the direct current Direct current power shifting network which electronic tube [2. Similarly, other tubes, 33 and 34, also of the gaseous voltage regulator type, maintain a constant voltage across the" potentiometer l5.

The grid bias of space discharge device I2 consists of two parts, the fixed voltage. drop acrossv potentiometer i5 and the D. C. output voltage across resistor II which is connected in parallel with the cathode resistor 9.

The operation of this portion of the circuit is substantially as follows: If it is assumed that there. is no outputv voltage across the load resistance. ll, moving the contact of the voltage potentiometer 1-5 up from. the negative end will increase. the positive potential on the control grid I3 of the electronic tube 12. Consequently, the plate-l6 will draw current. This increase in plate current will. increase the current in the direct current winding and thus increase the saturation of the saturable reactor, thereby decreasing the inductance of. its alternating current windings A corresponding shift in the phase angle of the current: will accompany this decrease in.-inductance,.shifting the phase of the current in the secondaryv of the transformer 21. The firing point of the thyratrons 3| and 32, and the other four :thyratrons. which are not shown will, therefore, be advanced. In this manner, an effective control is established overthe firing tubes; which, inturn, control the firing of the ignitrons 31 through 42. In axiidtion, since the; output voltage across the load resistance It is effectively connected in parallel with the variable voltage potentiometer i5,1it isobvious that the direct current output voltage will necessarily have to rise tomatch the preset value on the voltage potentiometer l5. action of the networks indicated by numerals 24 and: 25*, which. feed the four firing tubes which are-not shown, is identical to that just described for the. network 23..

i Asdescribed, the: circuit will automatical- 1y; compensate for output voltage-variations due to any cause. A dropor rise in the output voltage will change thephase. in the alternating current. windings." of the saturable re-- actors andautomatically change the output voltage so that it. will be equal to the preset value on the :voltage potentiometer l5. current'f'ailures in the plate circuit of the electronictube l2, due. to a possible fault indirect current supply; will automatically reduce the. phase in the alternating current winding of the saturable reactors, and hence the phase of the ignitrons, thereby decreasing the output voltage. Thustit will be apparent that by my arrangement acircuitis provided in which control means are incorporatedWfor regulating the direct current It should be understood that the In addition,

4 output voltage at high currents of a half-wave rectifier.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. An electronic voltage control circuit com prising, in combination, output terminals, a rectifier for producing a direct current output voltage across said output terminalaaphase shifting network including a space discharge device having a cathode, a grid and an anode, a cathode resistor connected to said cathode, said cathode resistor beingconnected across said output terminals, said grid being adapted to be biased at least in. part by a regulated direct current voltage, a saturable reactor, said anode being connected in series with said saturable reactor and means including said saturable reactor for varying the conductivity of said rectifier, said means being controlled by said phase shifting network.

2. An electronic voltage control circuit comprising,v in combination, output terminals, a multi-p hase rectifier for producing a direct. current output voltage across. said output; terminals, a phase shifting network includingan electronic space discharge device having a'cathode, agrid and an anode, a cathode resistor connected'to:

said cathode, said cathode resistor being: connected across said output terminals,.said grid; connected to a regulated directcurrentvoltage,

a plurality of saturable reactors, said anodabeing connected in series with said plurality'tol. saturable reactors, and means including saidiplurality of saturable reactors for varying the'conductivity of said multi-phase rectifier, said means being controlled by the current flowing through said saturable reactors.

3. An electronic voltage control device comprising in combination, output terminals, a rectifier for producing a direct current output. volt age across said output terminals, a phase shifting network including a space discharge device regulated for constant gain having a cathode, acontrol grid, an anode and an auxiliary grid, said' auxiliary grid being biased by a constant voltage, a cathode resistor connected to saidcathodesaid cathode resistor being connected across said outputterminals, saidcontroi grid being adapted to be biased at least in part by a regulated direct current voltage, a saturable reactor, said anode being connected in series with said saturable reactor and means including'said saturable reactor for varying the: conductivity of said rectifier, said means. being controlled by" said phase shifting network,

HUBERT H. WITTENBERG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,870,022. Prince Aug. 2, 1932 2,083,382 Jutson et al. June 8,. 1937- 2,095,827 Moyer .c Oct, 12, 1937 2,196,680 Milarta Apr. 9, 1940 2,315,619, Hutcheson etal. .Apr. 6, 1943 2,554,837 Meszaros May 29,1951 2,567,797

Anderson Sept. 11, 1951

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